Progressive Pitch

[Ron Hill]

People have often asked me about props, as if I really knew something. The truth is I know all about props. If you put one on your boat and the boat goes like "JACK the BEAR" you buy it, not one like it..THAT ONE...

Over the years I've made many props. I know people get confused about prop measurement, but today I thought I'd show you what PROGRESSIVE pitch really is, and what I have come to figure out why it works the way it works...

First picture is a 26 pitch Signature Drag Prop...

[Ron Hill]

Well I measure the blade in the middle and that is what I call it...

You see the little arrow, she points to 26....

[Ron Hill]

Now I usually like to measure the in pitch, the cutting edge pitch.

23 and a half, 24... right???

[Ron Hill]

Then I measure the trailing edge pitch, under the cup and divide by two... The cup give it more pitch, but cup sizes can vary and this his how I measure the... So, in at 24, out at 28, divide by 2, and you have a 26...

Why progressive pitch? At high spped there is air and water mixed, once the blade cuts the water, in order to keep the prop hooked up to the water, the air has to be squeezed out. So as the water goes up the blade the prop get better push of the tip of the blade because the water is packed tighter...

[Ron Hill]

This is me talking, no engineer....The leading edge (24 pitch), open it up and you slow the accelleration (in a perfect world), Say to 25, close it down to a 23, and you increase the low end "PUNCH"...

The trailing edge flap, as I like to call it, is where the speed comes from...Increase the pitch, lower the RPM's and increase the speed, in a perfect world...

This prop will be listed on E-bay for sale...
here's the listing, just an FYI!!!!

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=4508725824

[Jackpunx]

will the same concept work with Bravo 1 props?

[1badboat]

Super explaination Ron now tell us about cup, Rake, and how all of this stuff goes togather.

I have ran some of Ron's props his craftsmanship is superb. Maybe someday I can try one of his phone home signature series props.

[Carnivalride]

Ron,

Thanks for the information!:) :)

[Ron Hill]

Basically, there are no true pitch boat props made today...That I know of....

What I'd like to make would be a TRUE PITCH with a 15 degree rake....I think they might be seriously fast....I don't have that on my "TO DO LIST"...